The 2005 World Sustainable Building Conference, Tokyo, 27-29 September 2005

The 2005 World Sustainable Building Conference, Tokyo, 27-29 September 2005 (SB05Tokyo)

04-036

EXTENDED FRAMEWORK OF CASBEE; DESIGNING AN ASSESSMENT SYSTEM OF BUILDINGS FOR ALL LIFECYCLE STAGES BASED ON THE CONCEPT OF ECO-EFFICIENCY 1

Junko ENDO 2 Shuzo MURAKAMI Dr. Eng.3 Toshiharu IKAGA Dr. Eng. 4 Kazuo IWAMURA Pref. 5 Yuzo SAKAMOTO Dr.Eng 6 Tomonari YASHIRO Dr.Eng7 Kazuaki BOGAKI Dr.Eng. 1

Environmental Engineering Group, Nikken Sekkei Ltd.,2-18-3 Iidabashi, Chiyoda-ku, Tokyo, 102-8117, Japan, [email protected] Department of System Design Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa pref., 223-8522, Japan, [email protected] 3 Environmental Engineering Group, Nikken Sekkei Ltd.,2-18-3 Iidabashi, Chiyoda-ku, Tokyo, 102-8117, Japan, [email protected] 4 Faculty of Environment and Information Studies, Musashi Institute of Technology, 3-3-1 Ushikubo-Nishi, Tsuzuki-ku, Kanagawa pref., 224-0015, Japan, [email protected] 5 Department of Architecture, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan, [email protected] 6 Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan, [email protected] 7 Building Research Institute,1 Tachihara, Tsukuba city, Ibaraki pref., 305-0802, Japan, [email protected] 2

Keywords: BEE, performance, evaluation, labeling, stock management, PFI, floor rate

Summary This paper outlines the framework of basic and extended CASBEE tools as a structured assessment system called the "CASBEE family." It defines the basic concept of each tool and examines their applications in terms of building' life stages and their associated users. CASBEE (Comprehensive Assessment System for Building Environmental Efficiency) consists of a set of four basic assessment tools, namely "CASBEE for Pre-design" (CASBEE-PD), "CASBEE for New Construction" (CASBEE-NC), "CASBEE for Existing Building" (CASBEE-EB) and "CASBEE for Renovation" (CASBEE-RN). They correspond to the individual stages of the building's lifecycle. As an extended tool, "CASBEE for Temporary Construction" (CASBEE-TC) assesses temporary buildings to be constructed for the short-term service. "CASBEE for New Construction (simplified)" was also developed to meet the growing need for a simpler version of CASBEE-NC. Further, these tools can be modified to meet local conditions. "CASBEE Nagoya" and "CASBEE Osaka" have been implemented as local modifications of CASBEE. There are also needs for detailed assessment targeting specific environmental aspects. "CASBEE-H" assesses efforts made in buildings to alleviate the heat island effect. Finally, this paper examines a new assessment tool extended to the assessment of a group of buildings, called "CASBEE for District/Region (tentative)."

1.

Introduction

Since CASBEE, Comprehensive Assessment System for Building Environmental Efficiency, has launched in 2002, the movement towards sustainable construction continues and methods for evaluating the environmental performance of buildings have attracted more interest around the world. Recently, demand for these methods emerged for several practical purposes in Japan. For instance, under the Environmental Protection Ordinance (enacted December 2000), Tokyo Metropolitan Government became the first local authority that obliges all building owners intending to newly build or rebuild a building with floor area over 2 10,000m to submit a planning document assessing the environmental performance of the building, though not by using CASBEE in that case, in 2002. The content of these submissions is published on the Internet to disclose information on the environmental performance of buildings, to indicate the degree of effort for environmental protection made by the building owners, designers and related parties. Since then, some local governments have followed this style of policy promoting sustainable buildings. In April 2004, the city of Nagoya introduced a building assessment system called CASBEE Nagoya, based on CASBEE. The city of Osaka also adopted guidelines for Osaka Municipal Comprehensive Assessment System for Building Environmental Efficiency (CASBEE Osaka) in May 2004, and introduced the system in October 2004. Similar moves are under way in regional governments throughout Japan.

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The 2005 World Sustainable Building Conference, Tokyo, 27-29 September 2005 (SB05Tokyo)

This paper outlines the framework of basic and extended CASBEE tools as a structured assessment system called the "CASBEE family." Developed with the support by Japanese Ministry of Land, Infrastructure and Transport, the CASBEE family are developed and extended to meet those diversifying demands. Each tool is described in outline, and its applications are examined in terms of building's lifecycle and their associated users.

2.

Basic Conditions for Developing CASBEE

2.1

Three Major Concepts for CASBEE

CASBEE is based on three major concepts, and its development and extension are consistent with these basic concepts. Firstly, CASBEE is designed for assessment of buildings, which corresponds to their lifecycle. Secondly, it is based on the concept that clearly distinguishes environmental load (L) and quality of building performance (Q) as the major assessment targets. Thirdly, CASBEE applies the concept of ecoefficiency as BEE (Building Environmental Efficiency). Given L and Q, BEE is defined as Q/L to indicate the overall result of environmental assessment of buildings. 2.2

The basic approach to CASBEE Development

CASBEE has developed in accordance with the following principles: 1) The tool should be a positive assessment tool for designs with superior environmental consideration, rather than simply a negative checklist, to motivate designers, clients and others to be more interested in using it. 2) The assessment system should be kept as simple and comprehensible as possible. The scoring criteria should make maximum use of existing, established assessment methods, and aim for conformity with those methods, in order to save time and money in the assessment process. 3) It should be a general-purpose tool, able to evaluate buildings with wide-ranging types and sizes. These types include offices, schools, retailers, restaurants, halls, factories, hospitals, hotels, and apartments. To ensure widespread use, it should have a flexible structure able to reflect innovative initiatives taken by users based on their organizational circumstances. 4) It should take into consideration issues and problems particular to Asia and Japan.

3.

Applications of CASBEE

CASBEE is intended to serve applications for both public use and private use. It can be described according to the three major uses of CASBEE. 3.1 Application to public policies (1)

Application to building administration

Local governments seem to be the most active in adopt CASBEE for their building administration. The city of Nagoya has been running its system for building environmental assessment under the Environmental Preservation Act to promote sustainable buildings in the municipal since April 2004. It 2 requires all building owners intending to newly build or rebuild a building with floor area over 2,000 m to report the results of an assessment of the building by CASBEE Nagoya. The summary of each report will officially be announced on Nagoya City’s website. In Nagoya, buildings subjected to the system account for about 2% of all new buildings in number, and about 50% in terms of total floor space each year (Noda, 2004). Further, it is possible to give incentives to buildings which earn high ratings with CASBEE. In May 2004, Osaka adopted guidelines called CASBEE Osaka, and the system has been in effect since October 2004. 2 This applies to buildings over 5,000 m of total floor space that is included in floor are ratio, or buildings of 2 over 1,000 m of site area. These buildings will cover approximately 40% of total floor area of new construction every year in Osaka city. The city of Osaka is the first municipality to make rating by CASBEE Osaka a condition for permitting buildings to qualify for the administrative scheme called “sougou sekkei seido,” in which the maximum floor-area ratio of the building can be increased. The rating should reach at least the third of CASBEE’s five grades (B+ class) if the approval is given to the building being assessed (Osaka City, 2004). (2)

Use in selection of design competition proposals, and of PFI project operators

We anticipate that CASBEE will be used for scoring design competition proposals, selecting PFI project operators and checking environmental performance of buildings at the design stage. The CASBEE rating can also be used between building clients and designer, or between owners and occupants, to determine environmental targets. A CASBEE rating could be specified to designers as a design condition by privatesector project clients, as well as by local authorities, and designers could use it to raise their scores in

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pursuit of the maximum level of environmental performance that can be achieved within a given budget. It is also possible to extend the use of CASBEE to compliance to the public, such as information disclosure. (3)

Certification by a third party

The CASBEE rating is now subjected to third-party certification. A training program is also available to become an accredited assessor for CASBEE. Public use of CASBEE demands a higher level of fairness and confidence in the assessment results. Those systems are expected to become popular, although assessment by CASBEE is primarily a voluntary activity. 3.2 (1)

Application for Businesses For designers to employ design for the environment (DfE)

CASBEE can serve as an assessment tool that designers can use to check the environmental performance of buildings at the design stage by themselves, and provide their clients and others with objective information on environmental considerations. It can also be used as an indicator for the indirect setting of targets that clients, designers and others can use to evaluate their own environmental management activities under ISO14001 and other management systems. The assessment results can be used for self-declaration of the building performance. (2)

Environmental labeling that can be used in the asset valuation of buildings

Environmental labeling of buildings is also possible through certification by a third party, when buildings are valued as assets. Organizations can improve their corporate image through such labeling activity for the environment. Furthermore, CASBEE can be used as a tool to generate proposals for building operation monitoring, commissioning and upgrade design with a view to ESCO (Energy Service Company) projects and building stock refurbishment. CASBEE has the potential to be utilized in several stock management situations. 3.3

Application for Education

For specialized education, such as university and college courses of architecture, CASBEE can be used as a teaching resource. It is also useful as training material for professional CPD programs.

4

Framework of CASBEE: The CASBEE Family

4.1

Building Lifecycle and Basic Assessment Tools

CASBEE, the Comprehensive Assessment System for Building Environmental Efficiency, consists of a set of four basic assessment tools: "CASBEE for Pre-design"(CASBEE-PD), "CASBEE for New Construction"(CASBEE-NC), "CASBEE for Existing Buildings"(CASBEE-EB) and "CASBEE for Renovation"(CASBEE-RN), as shown in Table 2. Table 2 Names CASBEE for Pre-design CASBEE for New Construction CASBEE for Existing Building CASBEE for Renovation

CASBEE’s four basic assessment tools Abbreviation CASBEE-PD CASBEE-NC CASBEE-EB CASBEE-RN

Tool number Tool-0 Tool-1 Tool-2 Tool-3

Development schedule to be completed by July 2005 completed in July 2003 completed in July 2004 completed in March 2005

They correspond to the individual stages of the building's lifecycle, i.e. pre-design stage, design stage and post-design stage “CASBEE Family” is the collective name for these four tools and the extended tools for specific purposes. Figure 1 presents the relationship between those tools and lifecycle of buildings. (1) CASBEE for Pre-design (CASBEE-PD) This tool aims to assist the owner, planner and others involved at the planning (pre-design) stage of the project. It has two main roles: 1) To assist in grasping issues such as the basic environmental impact of the project and selecting a suitable site. 2) To evaluate the environmental performance of the project at the Pre-design stage. (2) CASBEE for New Construction (CASBEE-NC) This is a self-assessment check system that allows architects and engineers to raise the BEE value of the building under consideration during its design process. This tool, formerly named DfE (Design for Environment) tool, makes assessments based on the design specification and the anticipated performance. It can be used in design competitions, proposals and the selection of PFI operators. It can also serve as a labeling tool when the building is subjected to expert third-party assessment.

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The 2005 World Sustainable Building Conference, Tokyo, 27-29 September 2005 (SB05Tokyo)

(3) CASBEE for Existing Building (CASBEE-EB) This assessment tool targets existing building stock, based on operation records for at least one year after completion. It was developed to be applicable to asset assessment as well. Labeling is also possible by third-party agencies. (4) CASBEE for Renovation (CASBEE-RN) There is growing demand for building stock renovation, especially in Japanese market. In the same way as “CASBEE for Existing Building,” this tool targets existing buildings. It can be used to generate proposals for building operation monitoring, commissioning and upgrade design with a view to ESCO (Energy Service Company) projects, which will be increasingly important in future, and for building stock renovation. This tool is designed for ascertaining the degree of improvement (increased BEE), relative to the level that preceded renovation. Labeling is also possible by third-party agencies. Design process

Pre-design

Building lifecycle

Planning

Tool-0 CASBEE for Pre-Design Tool-1 CASBEE for New Construction

Design New Construction Basic design

Design for Construc execution tion

Pre-design assessment of building planning, site selection etc.

Post-design Renovation Operation

Design

Operation

Construct ion

Labeling

Assessment of new construction (Assessment of design specification and anticipated performance)

Labeling Assessment of existing buildings (Assess the actual specification and performance realized at the time of assessment)

Tool-2 CASBEE for Existing Building

Labeling Assessment of existing buildings (Assess the actual specification and performance realized at the time of assessment) Assessment of renovation (Assess improvement of specification and performance)

Tool-3 CASBEE for Renovation

Figure 1

Labeling

Building Lifecycle and the Four Assessment Tools

4.2 Outline of the Basic Assessment tools Among the four basic CASBEE tools, further details of completed tools are presented in the following section. 4.2.1 CASBEE for New Construction CASBEE-NC assesses buildings at the design stage for new construction. At the Preliminary Design, Execution Design and Construction Completion phases, the environmental quality and performance of the building and its load reduction performance are evaluated. As environmental performance and assessment criteria change over time, the results of assessments under “CASBEE for New Construction” only remain valid for three years after the completion of construction. After that limit, buildings are evaluated using “CASBEE for Existing Building.” Replacement construction is also evaluated under “CASBEE for New Construction.”The scoring criteria used for CASBEE are updated over time to reflect changing perceptions of the environment and technological innovations. Therefore, the latest scoring criteria of CASBEE-NC available at the time of assessment must be used to make assessments. The criteria are set with the aim of achieving widespread use. The criteria use energy-saving standards (PAL/ CEC values) and the Housing Performance Indication System, so that assessor can make use of existing data to facilitate assessment. The tool evaluates according to information that becomes progressively more detailed in each phase, from the Preliminary Design to Design for Execution and Construction Completion. Also, the tool configuration provides specific information for reference concerning environmentally conscious design at each phase. A number of buildings have assessed by CASBEE-NC, and several assessment results for research purposes have been reported since CASBEE-NC was published. A study of current BEE labeling results found the average of BEE values to be between 0.8 and 1.0 in the 34 samples (Ikaga, 2004). This demonstrates that CASBEE can be a satisfactorily practical labeling tool based on comprehensive building assessment. Further assessment cases may enhance the reliability of this method. 4.2.2 CASBEE for Existing Building This assessment tool evaluates achieved performance or installation when the assessment is made. Buildings should be evaluated with reference to the latest scoring criteria of CASBEE-EB when the building is assessed, not the criteria in effect when the building was built. The result is valid for 5 years, and has to be

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revised using the latest version of the assessment tool, because the condition of the building may change over time. CASBEE-EB as an assessment system has a structure similar to CASBEE-NC (CASBEE for New Construction). It can be used as a labeling tool to declare the environmental performance of buildings. CASBEE-EB is also utilized to support building maintenance. Building owners, such as the real estate sector and large enterprises, may use it as a self-evaluation tool for mid-term and long-term management plans. The scoring criteria are continuously revised according to the latest technical innovations and the status of the environment. In principal, CASBEE-EB assesses buildings on the basis of recorded performance or measurements taken on site. However, for practical reasons, some exceptions are allowed. For instance, the criteria of CASBEE-NC are applied when determination of the current performance level of the building is possible from drawings and specifications. Also, the criteria of CASBEE-NC are applied if site measurement is technically difficult, or if the result of assessment based on drawings and specifications appears to be more precise than assessment based on site measurements. Site measurement is necessary for some scoring criteria, such as luminance and noise level, as it is more precise and easier than simulation. CASBEE-EB allows using data taken from measurements mandated by regulations, such as indoor air quality and outdoor noise level. Records and measured data are necessary for scoring higher than level 3. In return, large amount of work for data collection can be avoided in some cases for lower scorning, at level 2 and 1. Assessment criteria for durability and longevity consider management practice. They require documentation to prove that the management level is consistent with the performance level that the criterion requires. Some assessment examples by CASBEE-EB are shown in Table 2. These buildings are offices built between in 1960 and 2003, and some are also assessed by CASBEE-NC. Although there have not been many case, it can be seen that results of NASBEE-EB correspond well to those of CASBEE-NC. Figure 2 shows the distribution of these results, indicating that most buildings showed good results. It may be because most of the buildings in Figure 2 were built within the last 5 years, and scored good marks using CASBEE-NC,as well.

Table 2 Assessment results of sample office buildings evaluated by CASBEE-EB CASE

Building Type

A B C D E F G H I J

office office office office office office office office office office

Year of completion 2002 2003 1979 1992 1996 2002 2000 2003 1960 2002

Q

L

Rating

2.5 2.3 2.4 1.9 3.0 2.9 3.4 3.4 1.5 3.1

68 67 64 64 78 73 75 74 65 72

28 29 27 35 26 25 22 22 45 24

A A A A S A S S B+ S

BEE=3.0

100 Q : B uilding E nvironm ental Q uality & P erform ance

BEE

S

BEE=1.5

BEE=1.0

BEE of CASBEE-NC 2.8 2.2 3.0 3.6 3.3 -

B

B+

A

B-

50 BEE=0.5

; Buildings built before 1999

C

; Buildings built after 2000

0 0

50

100

L : Building Environmental Loadings

Figure 2

CASBEE-EB Assessment results for sample offices

4.2.3 CASBEE for Renovation CASBEE-RN is designed to evaluate the performances of existing buildings based on predicted performance and specifications with renovation. It is valid for three years after completion of the renovation work, and

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assessment must be made with the latest version of CASBEE-RN at the point of assessment. This tool can be used to evaluate the degree of improvement (increased BEE), relative to the level that preceded renovation. That is only possible when the condition of the existing building before renovation has also been assessed. The example of CASBEE-RN’s result is presented as shown in Figure 2. CASBEE-RN may also assess improvement of specific performance in relation to the purpose of the renovation. For instance, the BEE for energy saving can be presented, that is determined by the scores for assessment categories especially related to energy saving renovation, such as Energy(LR-1) and Indoor environment(Q-1). (2) Results of Comprehensive Assessment for Building Environmental Efficiency (2)-1 Building Environmental Quality & Performance and Load Reduction (Results by Category) Radar Chart

Q. Building Environmental Quality & Performance Q-2 Weight 5

3

Q-1

Weight ＝0.4

Q-1

Weight ＝0.3

4

5

1

4

LR-1

LR-3

Weight ＝0.4

Weight ＝0.3

Weight ＝0.3

3.3

2.4

2.5

3.0

2.1

3

3.1

2

1

1

Noise & Acoustics

Lighting & Illumination

Thermal Comfort

Air Quality

4.0

2

3.0 3.0

3.0

3

3.4

3 2.1

2.0

1

1.0 Preserv ation & Creation of Biotope

Building Thermal Load

Natural Energy Utilizatio

4.0 3.0

2.8 3.0

3.0

3.0

2

Eff iciency in Building Service System

2.0

2

2.0

2.0 2.0

1.0

1

Ef f icient Operation

Local Characteristics & Outdoor

5.0

2.0 1

Townscape & Landscape

4

4 4.0

Flexibility & Adaptability

S LR3 ＝ 2.1 → 3.3

5

5

3.0

2

　　　LR-3

　　 S LR1 ＝ 2.4 → 3.5 　　S LR2 ＝ 2.2 → 3.0

4

2.5

　 SLR = 0.4* SLR1 + 0.3 * SLR2 + 0.3 * SLR3

LR-2

5

Durability & Reliability

3.0 2.0

2.3

Service Ability

3.5

3

3.1 2.1

S LR = 2.2 → 3.3

Score:

LR-1

4.0 2.6

2.3

2

LR-2 　　LR. Reduction of Building Environmental Loadings

3.0

4 4.0

3.0

2.0

S Q3 ＝ 1.7 → 3.4 5

4 3.0

3

3

Q-3

5

0

Score:

　SQ = 0.4* SQ1 + 0.3 * SQ2 + 0.3 * SQ3

　　　Q-2 S Q2 ＝ 2.3 → 3.2

　　 S Q1 ＝ 2.4 → 3.1

Score:

Q-3

2

S Q = 2.2 → 3.2

Score:

＝0.3

Water Resources

1

Materials of Low Environmental Load

Noise, Vibration and Oder

Air Pollution

Wind Damage

Light Pollution

Heat Island Ef fect

Load on Local Inf rastructure

(2)-2 BEE Building Environmental Efficiency Building Sustainability Rating based on BEE

Q : Building Environmental Quality & Perf ormance

BEE=1.5

BEE=3.0

100 S

BEE=1.0

B+

A

56

ＢＥＥ

Buildin g En viro nmen tal Qu ality & Pe rf orman c e Q B u ildin g Environ me n tal Loadin gs L

0.9

ΔＢＥＥ =

B-

50

=

BEE=0.5

ＢＥＥ (a fter RN) =

56 41

=

1.3

=

0.4

41

30

↑ 68

0 0

50

C

ＢＥＥ (before RN) = 100

30 68

* Q = 25 ＊ (S Q - 1)

L : Buildin g En viro nmen tal Loadin gs

L = 25 ＊ (5 - SLR)

Figure 3 Example of assessment result by CASBEE-RN (comparison between before and after renovation) 4.3

CASBEE for Specific Purposes

The basic CASBEE tool suite is applicable to a diverse range of individual applications. So far, CASBEE-NC has several extended tools shown in Table 3. Table 3

Extended CASBEE tools for specific purposes (as of March 2005)

Name CASBEE for Temporary Construction CASBEE for New Construction (simplified)

Application

Outline

Temporary Construction

Currently adapted to exhibition facilities.

Simple preliminary assessment

Simplified edition of CASBEE for New Construction.

―

For individual local areas

CASBEE-H

Assessment on the efforts in alleviating the heat island phenomenon

CASBEE for New Construction (Simplified), tailored to regional characteristics Detailed assessment of the heat island effect using CASBEE

4.3.1 Application to buildings for short-term use The tool “CASBEE for Temporary Construction (exhibition facilities),” published in July 2004, was developed as an extension to CASBEE for New Construction for evaluating temporary buildings constructed specifically

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The 2005 World Sustainable Building Conference, Tokyo, 27-29 September 2005 (SB05Tokyo)

for short-term use, such as Expo pavilions. Buildings of this type have short-term lifecycles, and therefore consideration must concentrate largely on material use and recycling in the construction and demolition phases. Also, these buildings have simple equipment and interior and exterior finishes. The scoring criteria reflect those features of this type of buildings. So far, the tool has been completed in a version limited to exhibition facilities. The current version of CASBEE for Temporary Construction (exhibition facilities) targets buildings that have lifetime within 5 years. Scoring criteria are based on those for halls of CASBEE-NC, and some modifications are made as follows; 1) The scoring criteria of Q-1 Indoor environment is lowered for background noise, because simple exterior materials with poor performance in sound insulation are often installed in temporally buildings. 2) “Durability & Reliability” and “Flexibility & Adaptability” in Q-2 Quality of service are excluded from scoring criteria. 3) In LR-2 Resource & Materials, “3R (reuse, reduction and recycling) of building materials” and “Minimization of waste disposal” are evaluated as additional assessment items. 4) Weightings are altered to reflect the importance of resource recycle and waste reduction in this assessment system. LR-2 gains heavier weight, and lighter weight is allocated for LR-1 Energy and Q-2 Quality of service. 4.3.2 Simple assessment Assessment using CASBEE for New Construction may take 3~7 days, including the time required to prepare documents necessary as the basis for scoring. CASBEE for New Construction (Simplified) was developed to meet the growing need for a tool to handle objectives such as those below. It makes a simplified, provisional assessment possible in around two hours (excluding time for the preparation of an Energy Saving Plan). 1) The need for simplified setting of the Building Environmental Efficiency level (as a tool for consensus forming between owners, designers and builders, etc.). 2) The need for setting environmental design targets and assessing attainment (as a proposal management tool etc. under ISO14001). 3) The need for preparation of documents for submission to government agencies, etc. (Environmental measures under construction administration, such as CASBEE Nagoya and CASBEE Osaka). 4.3.3 Consideration for regional character As noted above, CASBEE for New Construction (Simplified) can be used by local authorities in construction administration. Local authorities that use this tool can tailor it to local conditions, such as climate and prioritized policies. Changes are generally made by modifying the weighting coefficients. Such assessment can be made mandatory in the same way as an Energy Saving Plan, to be submitted to the authorities together with the building approval application, as a way to improve the environmental efficiency of buildings in the region. Flexible response to regional character is a common feature of all elements of the CASBEE family. One example is “CASBEE Nagoya.” CASBEE Nagoya has its own scoring guidelines that instruct some criteria in relation to local contexts, such as materials from local industry, and that define some excluding criteria. After CASBEE Nagoya began on April 1, 2004, the city received about 30 reports as of the end of July, and most of those buildings were labeled as class “B-“ or “B+.” Also almost no confusion was reported to the municipality over the operation of the system (Noda, 2004). It shows that the system effectively works for local application, so far. Another example is CASBEE Osaka that altered weighting coefficient from the original to reflect the high priority they give to heat island policy. The city of Osaka also started administrative use of CASBEE from October 1, 2004, changed the weights of Q-1 Indoor environment from 0.4 to 0.3 and Q-3 Outdoor environment on site from 0.3 to 0.4. 4.3.4 Detailed assessment of heat island impact Assessment of the heat island effect is essential in major urban areas, such as Tokyo and Osaka. CASBEE for heat island alleviation (CASBEE-H), draft completed in June 2004, is a tool aiming for more detailed quantitative assessment of heat island relaxation measures in building design. Q-3 Outdoor environment on site and LR-3 Off-site environment of the original CASBEE tool, CASBEE-NC, have some scoring criteria evaluating efforts against heat island effect. In CASBEE-H, the criteria deal with more detailed conditions in the outdoor thermal environment and heat island load to surroundings. To develop CASBEE-H, several studies have been made on urban-scale climate affected by measures taken in individual buildings. CASBEE-H is also evaluated with the concept of eco-efficiency. BEEH (Building Environmental Efficiency for Heat island relaxation), indicating efficiency in measures taken to reduce the heat island effect, as in equation (1).

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BEEH = Improvement of thermal environment inside the virtual boundary

(1)

Heat island load outside the virtual boundary Inside the virtual boundary defined by the borders of the building site area is the area where owners and designers can make efforts to improve the thermal environment of the site. The heat island load to the surroundings is evaluated by 1) the degree of increase in air temperature, and 2) the degree of decrease in thermal comfort. On the other hand, the thermal environment within the site is assessed by the improvement of thermal comfort in pedestrian areas under 2 or 3m height above the ground. 4.3.5 Extended tool for regional scale assessment CASBEE considers individual buildings, but it fully recognizes the importance of assessing building groups. Many recent city-center redevelopment projects have included plans taking into account the urban surroundings as one unit. For example, provision of public spaces on the site can be expected to have a positive effect on the surrounding environment, thereby improving environmental quality and performance (Q). Common restrictions imposed on all buildings on a site, even if each one has a different owner, can be regarded as efforts to improve the environmental performance of the urban area as a whole. Study has started on an extended CASBEE tool called “CASBEE for District/Regions” (provisional name) that will broaden assessment to cover efforts applied through either city-center renewal of urban districts, or development of large areas including multiple buildings.

5.

Conclusions

CASBEE is intended to serve various applications for both public use and private use, namely application for public policies, business and education. Local governments seem to be the most active in introducing CASBEE for practical use. 1) CASBEE consists of a set of four basic assessment tools: "CASBEE for Pre-design"(CASBEE-PD), "CASBEE for New Construction"(CASBEE-NC), "CASBEE for Existing Building"(CASBEE-EB) and "CASBEE for Renovation"(CASBEE-RN). They correspond to the individual stages of the building's lifecycle. 2) CASBEE-EB is presented as a new assessment tool with some case studies. 3) “CASBEE Family” is the collective name for CASBEE’s four basic assessment tools and the extended tools for specific purposes. 4) Some extended tools for specific purposes have been developed, such as CASBEE for Temporary Construction (exhibition facilities), CASBEE for New Construction (simplified) and its variations reflecting local conditions, CASBEE-H. 5) CASBEE Nagoya and CASBEE Osaka were first enacted in 2004 as tools for building administration to promote sustainable buildings. They also incorporated local context into their systems. 6) Study has started on “CASBEE for District/Regions” (provisional name) that will broaden assessment to cover efforts applied to areas including multiple buildings.

Acknowledgement The authors express sincere thanks to the Committee members of the Comprehensive Assessment System of Building Environmental Efficiency, and the Housing Bureau of the Japanese Ministry of Land, Infrastructure and Transportation for their extensive support for this study.

References Ikaga, T. 2004, CASBEE; New Labeling System Based on Environmental Efficiency, Proceedings of 6th Int. Conf. on EcoBalance, pp. 249-52. Murakami, S. et.al., 2002, Comprehensive Assessment System for Building Environmental Efficiency in Japan (CASBEE-J), Proceedings of Sustainable Building 2002 international conference. Noda, H. 2004, City of Nagoya’s Sustainable Building System characterized by Environmental Efficiency Evaluations and its Official Announcements. Proceedings of 6th Int. Conf. on EcoBalance, pp. 253-54. Osaka Municipal Government, 2004, Manual for Osaka Municipal Comprehensive Assessment System for Building Environmental Efficiency (CASBEE Osaka) (in Japanese) Institute for Building Environment and Energy Conservation, 2004, CASBEE Technical Manual 2004 Edition; CASBEE for New Construction, CASBEE for Existing Building, CASBEE for New Construction (Simplified), and CASBEE for Temporally Construction (exhibition facilities), (in Japanese) Murakami, S. et.al., 2004, Introduction to CASBEE, Japan Sustainable Building Consortium (ed.), Nikkei Business Publication Inc. (in Japanese)

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